I appreciate the responses. I've tried finding the Sheldon article about shimming, but am having trouble.

Alternatively, I found these headset reducers Amazon.com : Wheels Manufacturing Wheels Headtube Reducer Shims : Sports & Outdoors . Would they solve my problem and simply allow me to put a 1" threaded fork and 1" quill? What headset or other parts would you buy to use these things in my 1 1/8" threadless headtube? Maybe these are the things some of you were talking about.

Thanks,
Andy